The measurement of blood pressure is a common procedure used in hospitals, clinics, and other health care facilities to assist in diagnosing illnesses and monitoring patient health. In standard non-invasive blood pressure measurement practice, a patient's arterial blood pressure is measured using an inflatable sleeve, commonly referred to as a blood pressure cuff. The cuff is typically adapted to fit around a limb of the patient, and such cuffs are usually sized to fit around the patient's upper arm, between the armpit and the elbow. After placing the cuff around the upper arm, a bladder within the cuff is inflated to occlude the brachial artery, the primary blood vessel in the arm carrying blood away from the heart.
Blood pressure cuffs are typically available in a variety of standard sizes depending on the arm circumference (i.e., neonatal, child, and adult) of the patient. The Association for Advancement of Medical Instrumentation (AAMI) has published standards that suggest bladder dimensions for each of these categories. The AAMI standards indicate, for example, that the adult cuff bladder length should be approximately 0.80 times the circumference of the limb at the midpoint of the intended range of the cuff. This published AAMI standard also states that the width of the adult cuff bladder should be approximately 0.40 times the circumference of the limb at the midpoint of the intended range of the cuff. While these standard cuff ratios may be adequate for the majority of patients, such standard blood pressure cuffs are not well-suited for patients having arms with abnormally large circumferences.
Obese and/or muscular patients, for example, typically have arms with circumferences that are much larger than an average patient. In addition, for most obese patients, the distance between the armpit and the elbow is relatively short as compared to the arm circumference. Such arm geometry can pose challenges to health care providers when trying to properly occlude the brachial artery during non-invasive blood pressure readings. For instance, although obese patients may require blood pressure cuffs longer than the standard blood pressure cuffs described above to account for the circumference of their arms, the AAMI standards stipulate that the width of such a cuff bladder must increase as the length of the bladder increases. For most obese patients, however, the distance between the elbow and the armpit is typically not long enough to accommodate a blood pressure cuff with the stipulated increased width. Thus, while a blood pressure cuff sized for such patients may have a length adequate to encircle the circumference of the patient's arm, the width of such a cuff would extend beyond the patient's elbow. Under such a scenario, the bone structure of the elbow would hinder occlusion of the brachial artery during inflation of the cuff, causing blood pressure readings to be inaccurate. Also, covering the anticubital fasa makes the proper placement of a stethoscope impossible for a traditional manual blood pressure cuff reading.
Conversely, while it may be possible to construct a conventional single-bladder blood pressure cuff having a length sufficient to encircle such large circumference arms and a width sufficient to fit between the armpit and the elbow, such a hypothetical blood pressure cuff would inflate to have an undesirably narrow cross-section along the length of the arm before achieving the pressure required to occlude the brachial artery of obese patients. Generally, approximately 3 inches of cuff contact width is required between the armpit and the elbow for accurate blood pressure measurements during occlusion of the brachial artery. Thus, the width of such hypothetical cuffs would not maintain sufficient contact with the arm of the patient during occlusion, and blood pressure measurements obtained using such cuffs would also be prone to error.
The exemplary embodiments of the present disclosure are directed toward overcoming the deficiencies described above.